Management of council-owned trees

Introduction

This protocol is an operational document that sets out the council’s approach to managing its tree stock. It outlines our systems of management with the objective of maintaining canopy cover in an acceptably safe manner within the context of resources available. It is a working document that is updated and amended as appropriate. This protocol updates and replaces the 2021 version. It has been updated to:

1. Reflect relevant arboriculture guidance and best practice on the management and maintenance of tree stock, and
2. Take account that Cheltenham Borough Council and Cheltenham Borough Homes, as of 1 July 2024 are a single organisation. This protocol covers all assets across Cheltenham Borough Council ownership.

The protocol sets out our approach to risk management of publicly owned trees within Cheltenham. It does not relate to trees situated within the public highway (which are the responsibility of Gloucestershire County Council) nor trees on private or other land. It is striving to achieve a balance between the many and varied benefits of the existence trees in both an urban and rural setting and the risks posed by such trees through the implementation of what is reasonable and what is practicable in terms of management of such risk.

This protocol does not set out strategic policy in respect of trees. This is set out in the Cheltenham Plan and the Cheltenham, Gloucester and Tewkesbury Joint Core Strategy which in due course will be collectively replaced by the Cheltenham, Gloucester and Tewkesbury Strategic and Local Plan.

Background

Cheltenham has a long and distinguished history of tree cover dating back to the creation of the town and the then popular desire to plant both native and exotic trees. Some of these “original” trees are still alive today. However, the comparatively dense tree population in both private and public ownership fosters the same spirit of canopy cover, tree lined streets, and the varied and exotic nature of trees within public parks, gardens and open spaces of yesteryear.

The council has a duty of care to manage the risk posed by its trees under The Occupiers Liability Act 1957 and The Occupiers Liability Act 1984, and the Health and Safety at Work etc. Act 1974. However, there is not only a public safety concern but there are also more placemaking and sustainability desires including consideration of ecological, landscape and the visual amenity value of trees as well as all the other benefits to which trees contribute-storm water control, cooling effect in built up areas, visual amenity etc which come under consideration when managing trees. The council is not expected to guarantee tree safety, but it is expected to have a proactive risk management approach in relation to risks posed by its trees.

The protocol has been written following advice from the National Tree Safety Group publication “Common Sense Risk Management of Trees-Guidance on Trees and Public Safety in the UK for Owners, Managers and Advisors” (2011). This guidance is expected to be updated, when available this protocol will be appropriately adapted to reflect any relevant changes and best practice.
The guidance document above sets out five key principles which underpin this protocol:

1. Trees provide a wide variety of benefits to society,
2. Trees are living organisms that naturally lose branches and fall,
3. The overall risk to human safety is extremely low,
4. Tree owners have a legal duty of care,
5. Tree owners should take a balanced and proportionate approach to tree safety management.

This protocol also strives to be in accordance with and reflect guidance from the following:

• Arboriculture Association Guidance Note 7 “Tree Surveys: A Guide to Good Practice” (revised 2016)
• HSE document “Management of the Risk from Falling Trees or Branches” (2013)
• Gloucestershire Highways “Highway Tree Inspection and Routine Maintenance Policy” (2010)

Our risk-based approach to tree management

In this context, risk is considered to be a product of the likelihood of harm combined with the severity of consequences from a particular hazard. The risk from trees is therefore to the public and property, not only on council land but also on the highway, railway and other public and private places. The risk addressed ranges from the threat of actual personal physical impact to the threat of damage to property.

Indirect property damage and other personal impact (e.g. the threat of property subsidence, perceived nuisance such as falling leaves, TV reception, shade etc.) is not addressed in this protocol.

This document relates to the management of Cheltenham Borough Council trees in parks, gardens, open spaces, allotments, car parks cemeteries, watercourses, woodlands, housing forecourts trees and trees on other land belonging to and managed by Cheltenham Borough Council.

The primary method of controlling the risk posed by trees is to cyclically and periodically inspect them for “defects” or a variation from a perceived norm of the tree species using Visual Tree Assessment (VTA). Most types of hazards that can occur in a tree can be detected from external visual assessments. The council’s tree team is experienced in the VTA method and observe and diagnose signs of a tree’s external response to potential hazards such as cracks, decay, physical damage, adverse growing conditions, and other growth-related defects.

It is considered that the risk of the consequence of failure posed by a small tree in the middle of a large open space where there is no public access is different to a large tree in a town centre park. As such this protocol sets out a zoning approach which reflects the perceived risk-taking account of the size and maturity of on-site trees and the frequency of adjacent usage as well as adjacent targets within falling distance of the trees in question.

This zoning is based on the following:

• Zone 1*: Inspected every 12 months. This includes a detailed inspection on a 24-month cycle together with an interim 12 months “walk by” inspection. These trees are within Montpellier Gardens, The Hatherley Park poplar (T131) and Naunton Park poplar (T28). Given the condition and maturity of the many mature lime trees within the busy Montpellier Gardens.
• Zone 1: Inspected every 18-24 months. Trees adjacent to the A40, A435, large trees adjacent to Tewkesbury Road, Pittville Lawn, The Poplars (mature trees close to private property), Royal Well, St Mary’s Churchyard and other locations where there is a presence of large, mature trees in high use areas.
• Zone 2: Inspected every 24-36 months. Trees within parks, gardens and open spaces in frequently used but lower usage areas. Such locations include Cox’s Meadow, Lansdown Crescent Green, Fairview Rd open space, Pittville Park Open Space, Wellington Square, public car parks, Housing forecourts, Bouncers Lane cemetery, car parks.
• Zone 3: Inspected every 36-48 months. Trees in less used public open space especially where the average size and species of tree is less likely to cause injury or property damage. Such locations include: Pilley Bridge Nature Reserve, allotments, Sandy Lane Playing Field, Charlton Park.

In the overwhelming majority of cases, each tree will be inspected and recorded. However, in several situations, this is impractical (such as woodlands and other areas of dense tree population numbers). Tree conditions may also be recorded in groups.

Trees subject to officer inspection and recorded are located in parks, gardens, open space, car parks, cemeteries, woodlands, as well as other land belonging to this council such as Housing forecourts, allotments, The Minster and St Peter’s Churchyard. Trees situated within the adopted highway are under the management of Gloucestershire Highways. Gloucestershire County Council manage trees within various parcels of land under their management within Cheltenham as well as schools (where appropriate), libraries etc. Trees on private land are not managed by Cheltenham Borough Council nor assessed by the tree team.

There are a range of factors which are taken into account in the management of risk. It should be emphasised that risk arising in respect of trees is not static and therefore the role of inspections and observations are key. With this in mind, it is important that the council adopts a dynamic approach to managing risk and should this protocol need to be updated to respond to issues arising from inspections and observations then this will be undertaken.

Method of trees inspection

Differing types of inspections are undertaken according to the specific site:

1. No routine inspection but officers undertake a reactive response to reports of tree damage or threat (e.g. Leckhampton Hill). To support this, there is close engagement with the council’s green spaces team that manage Cheltenham Borough Council assets at Leckhampton Hill and directly undertake land management.
2. Informal observation undertaken by tree team/green spaces team/local interest groups/Ubico with good local knowledge and familiarity of local trees (e.g. Cheltenham Tree Group). When reports are logged either formally by the groups above or members of the public, the defects are assessed by the tree team and any significant subsequent works are documented.
3. Formal inspections such as “walk by” inspections of trees on public land (eg Benhall Woods, Honeybourne Line) where it is not reasonable or practicable to undertake or document an inspection of each tree but details of significant trees and their defects are usually documented. Any follow-up remedial tree surgery and felling is documented.
4. Detailed inspections of trees which are or there is a risk may cause a significant risk to persons and property. This is usually undertaken by individual visual inspection from the ground of the physiological and biological condition of trees and based on arboricultural experience and knowledge via a VTA. Defects are recorded and subsequent tree surgery work prioritised.

Subsequent appropriate tree surgery work will be in the spirit of good arboricultural practice and in accordance with BS3998 (2010) Tree Work – Recommendations. The council procures the majority of its tree surgery externally. Such trees inspectors should hold the level 3 LANTRA Professional Trees Inspection qualification (or be working towards such a qualification and under supervision by someone qualified). Trees under this inspection management regime are zoned according to their location based on an estimation of a combination of the “frequency of use” of an area and the size of the trees therein.

Interim visits to parks, gardens open spaces by the tree team and green spaces team are frequently undertaken. However, details of casual observations of trees during such occasional visits are not usually recorded. Any reports by members of the public across the council’s green spaces are visited and then managed accordingly.

When possible, trees will be inspected during different seasons with a view to more clear assessment of the condition of physiological or biological condition. Individual and/or groups of trees subject to a detailed inspection are marked on a map and formally recorded on the in-house tree inspection digital recording system. Location, genera, species, size, maturity, defects and specific characteristics of such trees are noted, and remedial work is described and prioritised within the context of this protocol. Tree surgery/felling work generated as a result of such routine inspections is usually collated into a works contract and actioned in line with the Council’s procurement rules with the aim of achieving best value for the council.

Details of inspection records are maintained and archived.

Post extreme weather events

Following exceptionally windy weather, the trees team will visit and undertake a “walk-by” inspection of trees within 10 sites (following a strong gale (47-54 mph) or 18 sites following storm force winds (54mph+), these sites are listed in the appendix of this protocol. Post storm inspection sheets are retained. Such inspections occur as soon as possible after any such weather event. The trees team form part of the council’s emergency planning response, with contractors available to undertake any immediate works required.

Quantifying and evaluating risk posed by trees

Where the urgency of tree work is unclear, the use of Tree Hazard: Risk Evaluation and Treatment System (THREATS), or similar, may be used to assist in decision making. This provides a method for identifying recording and managing hazards from trees.

Where a more quantitative or detailed assessment of the structural integrity is required, the use of more intrusive diagnostic tools such as the use of a Resistograph and/or Pressler borer is used. If it is deemed necessary, independent advice is sought from a suitably qualified, experienced and insured tree consultant.

To support the assessment of risk posed by trees, the tree team maintain membership of either of the Arboricultural Association, The Association of Trees Officers, The International Society of Arborists or similar to be kept up to date of legislation, updated guidance and new approaches to arboriculture regarding tree safety, pests and disease and other relevant information.

Tree risk management and ash dieback

The consequences of ash dieback (ADB) are considered to be the most significant new risk from trees to persons and property since Dutch elm disease.

Latest observations (2024) consider ADB is not considered to be an immediate threat within the “urban confines” of Cheltenham. However, it is noted that a significant proportion of ash trees have early-stage contamination and these are subject to continued monitoring as a part of routine inspections.

However, in areas such as Leckhampton Hill and Pilley Bridge Nature Reserve as well as other more dense concentrations of ash trees the risk from falling trees and branch work is considered to be significant as trees die-back and roots/branch work become die back and become unstable, monitoring is ongoing.

It is not currently considered necessary to adjust the overall Inspection frequency to take account of ash die-back, however future observations may lead to a more formal approach to inspection frequency in places other than Leckhampton Hill (whose main footpath has a yearly (mid-late summer inspection). It may be that a change to the tree inspection protocol will be required as the degree and rate of decline accelerates. This is kept under regular review.

The council has allocated a defined budget to manage ADB. This is kept under review as the scale of anticipated costs remain largely unknown. An ADB Management Plan is in place and should be read alongside this protocol where this is relevant.

Trees on land not belonging to Cheltenham Borough Council

When possible, and upon request, advice is given to tree owners on private land as to how to go about responsibly managing their trees.

An operational working Arboriculture Protocol is in place which sets out the working relationship between Cheltenham Borough Council and Gloucestershire Highways. The intention is to formally review this annually.

A selection of appropriate professional arboriculture consultant contacts is publicised on our website. Such professionals are in a good position as to undertake detailed safety inspections of trees on non-council land. Similarly, when possible, appropriate advice is given to other statutory bodies on tree management upon request.

Category 1 = Strong Gale Force (47-54mph)

Category 2 = Storm Force (54mph+) all identified sites (category 1 and 2)